1367784 Joining metal strip; welding by pressure; abrading BRITISH FEDERAL WELDER & MACHINE CO Ltd 19 Sept 1972 [22 Sept 1971] 44094/71 Headings B3A B3R and B3D A method of welding metal strips in a flash welder includes locating and clamping the ends of metal strips 14, 15 in a clamp position, cleaning and shearing the ends of the strips and welding the sheared strip ends in the clamp position while they are clamped on the cleaned areas. The ends of the strips are held in clamps 10-13 and they are cleaned by four sanding wheels 19, which remove unwanted surface coatings from the full width of the strips. The ends of the strips are then sheared by elements 20 moving horizontally across the strips. Main clamps 11, 12 are opened and auxiliary clamps 10, 13 move the strip ends so that they project by a selected amount beyond the main clamps. These are then closed and the ends of the strips are brought into abutment to commence flash welding. A self-contained cleaning unit may be used in conjunction with a conventional flash welder, in which case the strip ends are cleaned after they have been aligned by means of a gauging bar. The cleaning unit is withdrawn prior to advancing the strip ends into abutment for welding. Cleaning may be performed by laminated sanding wheels, solid or flexible grinding wheels, sanding discs or sanding belts, or by sand or shot blasting. Cleaning may be restricted to either the upper or lower surfaces of the strip ends and when sand or shot blasting nozzles are fitted, they are mounted in pairs, i.e. one nozzle for each strip, to remove the surface coatings from the upper and/or lower strip surfaces.
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